Similar to Kaden's Thread "Suggestions"

[Waffuru]

You only get 300% XP while in a group and earn the person who referred you. Both of you get the bonus XP though, and it counts for turning in quests so it pays to be near when you turn in quests and not run off as soon as you turn it in.

There's also some difference in level that causes the higher level player to stop earning 300% but it's more than 1 level difference at least.